The present invention relates to a cooling system for a rotary internal combustion engine and, more particularly, to a water cooling system for a rotary engine especially suited to marine applications.
The rotary internal combustion engine or Wankel engine has gained significant acceptance and has been used more widely in automotive applications in recent years. One of the major attractions of the rotary engine is the relative simplicity of its construction as compared to the more conventional reciprocating piston engines. In addition, advances in engineering have eliminated or substantially alleviated design and operational problems previously associated with rotary piston engines, such as rotor seal efficiency and life. As a result, additional applications for rotary piston engines are being explored and adopted. One particularly attractive application for the rotary engine is marine use and, in particular, in outboard boat motors.
Although many automotive applications for rotary piston engines allow them to be air-cooled, there are both practical and manditory reasons for utilizing water cooling for rotary engines in marine applications. From a practical standpoint, there is a ready supply of water available for the cooling system in a marine engine. In addition, there are certain parts of any marine engine, which would include a rotary engine, that must be so thoroughly cooled that air-cooling would be ineffective and unacceptable. One such area of a marine engine is the exhaust manifold which, by U.S. Coast Guard regulation, cannot be hot and can only be effectively cooled to the required temperature level by water cooling.
Thus, a water cooling system for a rotary piston engine used in an outboard boat motor must not only provide the required cooling for the hot exhaust manifold, but should also utilize the water to effectively cool other high operating temperature parts. However, the cooling system should also be relative simple so as not to unduly complicate the relatively simple construction of the rotary piston engine. Further, the water cooling system should be adaptable for application to either a single or a double rotor engine, these being the only two of any significant practical application.